Credit Quality (Summary of Average Impaired Loans and Leases and Interest Income by Class) (Parenthetical) (Detail) $ in Millions	3 Months Ended				6 Months Ended				12 Months Ended
	Jun. 30, 2018 USD ($)		Jun. 30, 2017 USD ($)		Jun. 30, 2018 USD ($)		Jun. 30, 2017 USD ($)		Dec. 31, 2017
Financing Receivable, Impaired
Average Recorded Investment	$ 1,581		$ 1,743		$ 1,546		$ 1,796
Number of contracts	2,273	[1],[2],[3],[4]	2,430	[5],[6],[7],[8]	4,544	[1],[2],[3],[4]	4,489	[5],[6],[7],[8]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Impaired
Average Recorded Investment	$ 16		$ 38	[9]	$ 20		$ 42	[9]
Number of contracts			2	[5],[6],[7],[8]	2	[1],[2],[3],[4]	7	[5],[6],[7],[8]
Commercial Portfolio Segment | Commercial Mortgage Loans, Owner-occupied | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Impaired
Average Recorded Investment			$ 26
Number of contracts			5						5

[1] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[2] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[3] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[4] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[5] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[6] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[7] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[8] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[9] Excludes five restructured loans associated with a consolidated VIE in which the Bancorp had no continuing credit risk due to the risk being assumed by a third party, with an average recorded investment of $ 26 for both the three and six months ended June 30, 2017. An immaterial amount of interest income was recognized during the six months ended June 30, 2017. Refer to Note 9 for further discussion on the deconsolidation of the VIE associated with these loans in the third quarter of 2017.